Injector pump apparatus



Dec. 15, 1970 c. A. MILLER INJECTOR PUMP APPARATUS I Filed March 5, 1969 wfiwm a. 7 l a 6 5 ma 8 .II w

AT TORNE Ys United States Patent F 3,547,560 INJECTOR PUMP APPARATUS Carl A. Miller, St. Paul, Minn., assignor to Economics Laboratory, Inc, St. Paul, Minn., a corporation of Delaware Filed Mar. 5, 1969, Ser. No. 804,428 Int. Cl. F04b 17/00 US. Cl. 417375 7 Claims ABSTRACT OF THE DISCLOSURE A body defining therein a generally cylindrical, elongated chamber with a portion adjacent one end having a cross-sectional area substantially smaller than a portion adjacent the opposite end, a dual-acting piston mounted therein for reciprocal movement with rolling diaphragms aifixed between the ends of the piston and the walls of the chamber to form fluid tight compartments between the end faces of the piston and the ends of the chamber, a spring biasing said piston toward the end of the chamber having the larger cross-sectional area, a first passageway through said body in communication with the compartment having the larger cross-sectional area, a second passageway through said body in communication with the compartment having the smaller cross-sectional area and a third passageway through said body in communication with the compartment having the smaller crosssectional area containing a check valve for allowing a flow of fluid only into the compartment. Connecting the first passageway to a common conduit having a flow of pressurized fluid therein produces a differential pressure across the piston causing it to move against the bias, toward the end of the chamber having the smaller crosssectional area, and inject into the conduit fluid contained in the smaller end of the chamber. Removing or reducing the pressure on the fluid in the conduit, sufficiently, allows the bias to return the piston to the normal position, whereupon, fluid to be injected into the conduit is drawn into the chamber through the third passageway.

BACKGROUND OF THE INVENTION Field of the invention In many commercial processes relatively small quantities of one liquid must be added to relatively large quantities of a second liquid to perform various tasks. For example, in commercial or institutional dishwashing machines rinse additives are mixed with water for use in the rinse cycle. The first liquid or additive is generally injected into a stream of the second liquid while it is flowing into the machines utilizing the liquids. Injecting one liquid into the other in this manner provides a number of advantages, such as adequate mixing of the liquids, proper dilution of the liquids prior to placing them in the machine, etc.

Description of the prior art In general, prior art devices utilize a piston or the like reciprocally mounted in a chamber having first and second passageways in communication therewith and each passageway having a check valve for unidirectional flow therethrough. The piston is operated by some external power source which moves the piston in a first direction to draw liquid into the chamber through one of the passageways, after which the piston is moved in the opposite direction to force the liquid out through the other passageway to inject it into the main stream of liquid. Generally the prior art devices require external power sources to operate the pistons and some apparatus for metering the 3,547,560 Patented Dec. 15, 1970 SUMMARY OF THE INVENTION The present invention pertains to injector pump apparatus including a body defining a generally cylindrical, elongated chamber therein with a cross-sectional area adjacent one end smaller than the cross-sectional area adjacent the opposite end, a dual-acting piston mounted therein for reciprocal movement, sealing means positioned between said piston and said body for dividing said chamber into first and second compartments and preventing fluid communication therebetween, biasing means urging said piston toward the portion of said chamber having the larger cross-sectional area, a first passageway in said body in communication with the end of said chamber having the larger cross-sectional area, and second and third passageways in said body in communication with said chamber at the end having the smaller cross-sectional area and said third passageway including a check valve for allowing the flow of fluid only into said chamber.

It is an object of the present invention to provide new and improved injector pump apparatus.

It is a further object of the present invention to provide injector pump apparatus including a dual-acting piston constructed so that fluid under equal pressure at opposite ends thereof produces a differential force thereacross, which force causes the piston to move.

It is a further object of the present invention to provide injector pump apparatus having adjustable metering means for controlling the flow of fluid injected by the pump apparatus.

These and other objects of this invention will become apparent to those skilled in the art upon consideration of the accompanying specification, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings, wherein like characters indicate like parts throughout the figures:

FIG. 1 is an axial sectional view of the injector pump apparatus; and

FIG. 2 is an enlarged detailed fragmentary view of a portion of FIG. 1, portions thereof broken away and shown in section.

DESCRIPTION OF THE PREFERRED \EMBODIMENT In the figures the numeral 10 generally designates a body including a generally tubular housing 11. The housing 11 has a radially outwardly directed flange 12 extending around the outer periphery thereof at the lower end (in FIG. 1) and the outer periphery of the flange 12 is threaded to receive in threaded engagement therewith a collar nut 13. Collar nut 13 is constructed somewhat similar to a standard nut with a radially inwardly directed collar or flange 14 formed integrally therewith at one end thereof. The opposite end of the housing 11 has threads formed in the outer periphery thereof for receiving a second collar nut 15 in threaded engagement therewith. The opposite end of the housing 11 also has a radially inwardly directed flange 16 with a tubular wall 17 formed integrally therewith and extending generally parallel with the outer wall of the housing 11 toward the first or lower side thereof. In this embodiment the tubular wall 17 extends approximately one-third the total length of the housing 11, although it should be understood that the length is up to the discretion of the manufacturer and is not critical. The inner surface of the housing 11 and the inner surface of the wall 17 within the housing 11 partially define a chamber or cylinder having a piston generally designated 20 operably mounted therein.

Piston 20 is an elongated dual-acting piston with a generally cylindrical body 21 the outer diameter of which is slightly smaller than the inner diameter of the wall 17. The lower end (as seen in FIG. 1) of the piston 20 has a radially outwardly directed flange 22 formed as an integral part thereof with a tubular wall 23 integrally affixed to the outer periphery thereof and extending generally parallel with the outer surface of the body 21. The outer diameter of the wall 23 is slightly smaller than the inner diameter of the housing 11 and a radially outwardly directed flange 24 at the upper end of the wall 23 slidably engages the inner surface of the housing 11 to maintain the piston 20 correctly positioned therein. The piston 20 has a first rolling diaphragm 30 coaxially positioned over the lower end thereof and a second rolling diaphragm 31 coaxially positioned over the upper end thereof. The first rolling diaphragm 30 is affixed to the piston 20 by means of a retainer plate 32 positioned in overlying relationship thereto and afiixed to the piston 20 by means of a screw 33 threadedly engaged through the retainer plate 32, diaphragm 30 and into the body 21. The second rolling diaphragm 31 is affixed to the piston 20 by means of a retainer plate 34 positioned in overlying relationship with the diaphragm 31 and affixed to the piston 20 by means of a screw 35 inserted through the retainer plate 34 and diaphragm 31 and threadedly engaged in the body 21 of the piston 20. The retainer plates 32 and 34 form oppositely directed faces of the piston 20 for the operation thereof which will be explained presently.

The rolling diaphragm 30 has an enlarged or ringshaped portion 40 at the outer periphery thereof which is positioned in a ring-shaped groove in the flange 12 of the housing 11 to secure the diaphragm 30 relative to the housing 11. The rolling diaphragm 31 has an enlarged or ring-shaped portion 41 at the outer periphery thereof which is engaged in a ring-shaped groove in the flange 16 of the housing 11 to secure the diaphragm 31 relative to the housing 11. The rolling diaphragm 30 has a rolling wall 45 which extends from the lower end of the piston 20 along the outer surface of the wall 23 somewhat less than the length thereof and is folded outwardly to extend back along the inner surface of the housing 11 to the ringshaped portion 40 at the outer periphery of the diaphragm 30. The rolling diaphragm 31 has a rolling wall 46 which extends from the upper end of the piston 20 along the outer surface of the body 21 downwardly somewhat less than the length of the Wall 17 and is folded outwardly so as to extend back along the inner surface of the wall 17 to the ring-shaped portion 41. The rolling walls 45 and 46 of the diaphragms 30 and 31 provide a seal between the piston 20 and the housing 11 while allowing axial reciprocal movement of piston 20 within the housing 11. It should be understood that other means of sealing the space between the piston 20 and the housing 11 might be devised by those skilled in the art but the diaphragms 30 and 31 are illustrated because of their simplicity and because of the effective sealing they provide with very little resistance to the movement of the piston 20.

A generally circular slightly concave end cap 50 is coaxially positioned over the open lower end of the housing 11 so that a surface thereof engages the axially outwardly directed surface of the flange 12 and maintains the ring-shaped portion 40 of the diaphragm 30 fixedly engaged in the groove of the flange 12. The collar nut 13 is threadedly engaged over the end cap 50 onto the housing 11 so that the flange 14 thereof engages the axially outwardly directed surface of the end cap 50 and maintains it in a fixed position relative to the housing 11. Thus, the ring-shaped portion 40 of the diaphragm 30 operates as a seal between the end cap 50 and the housing 11 as well as a means for holding the diaphragm 30 in the correct position. The end cap 50 has a generally axially extending passageway 51 therethrough which communicates with a compartment, designated 52, defined by end cap 50, diaphragm 30 and retainer plate 32 (or the lower face of the piston 20). The passageway 51 is in communication with a main conduit 53 through a branch conduit 54 threadedly engaged therewith.

A generally bell-shaped cap is positioned over the upper end of the housing 11 so that the axially outwardly directed end surfaces of the cap 60 bear against the axially outwardly directed surface of the flange 16 of the housing 11 with the ring-shaped portion 41 of the diaphragm 31 therebetween. The collar nut 15 is fitted over the bell-shaped cap 60 and threadedly engaged with the housing 11 to maintain the cap 60 in fixed abutment against the housing 11. The ring-shaped portion 41 of the diaphragm 31 serves as a seal between the cap 60 and the housing 11 as well as to maintain the diaphragm 31 correctly positioned. The bell-shaped cap 60 has an inner cavity therein with an inner diameter approximately equal to the inner diameter of the wall 17 in the housing 11. The bell-shaped cap 60, the diaphragm 31 and the retainer plate 34 (or the upper face of the piston 20) cooperate to define a compartment 61. A generally axially extending passageway 62 communicates with the compartment 61 at one end thereof and extends outwardly through the upper end of the bell-shaped cap 60. A radially inwardly directed shoulder 63 in the passageway 62 spaced from the compartment 61 a short distance serves as a stop for an indicator ball 64. In general, the ball 64 will be somewhat heavier than the fluid flowing in the passageway 62 so that it is always biased toward the shoulder 63 by gravity. If the body 10 of the apparatus is mounted so that the passageway 62 is not generally vertical, other means of biasing the ball 64, such as a spring, may be utilized. At least a portion of the bellshaped cap 60 defining the passageway 62 is formed of transparent material so that the position of the indicator ball 64 can be observed externally. In the present embodiment the entire bell-shaped cap 60 is formed of a transparent plastic for simplicity of construction.

A cavity 65 is formed in the upper end of the bellshaped cap 60 coaxially with the passageway 62 and with a diameter substantially larger than the diameter of the passageway 62. A passageway 66 is formed in the bellshaped cap 60 generally parallel with the passageway 62 so that the upper end thereof is in communication with the cavity 65 and the lower end thereof turnsradially outwardly to an opening in the exterior surface of the bellshaped cap 60. One end of a conduit 67 is threadedly engaged in the exterior opening of the passageway 66 and the other end of the conduit 67 is threadedly engaged with the main conduit 53.

An adjustable valve assembly generally designated 70 is positioned in the cavity 65 to provide communication between the passageway 62 and the passageway 66. The adjustable valve assembly 70 is illustrated in detail in FIG. 2. The assembly 70 includes a generally cylindrical body 71 having an outer diameter approximately equal to the inner diameter of the cavity 65. A portion of the outer periphery of the body 71 is removed around the circumference thereof adjacent the lower end so that an annular cavity 72 is defined between the inner surfaces of the cavity 65 and the outer surfaces of the body 71 when the assembly 70 is fitted into the cavity 65. A flexible O-ring 73 is positioned between the body 71 and the inner surface of the cavity 65 at the upper or axially outwardly directed end of the cavity 72 to prevent the leakage of fluid therebetween. The body 71 has a passageway formed therethrough which is coaxially aligned with the passageway 62 when the body 71 is correctly positioned in the cavity 65. An adjusting screw 75 is threadedly engaged in the central passageway through the body 71 to prevent the flow of fluid therethrough. A V-shaped notch 76 is formed in the outer periphery of the screw 75 so as to extend longitudinally from the lower end thereof a predetermined distance therealong. The notch 76 decreases in depth and width from the lower end of the screw 75 toward the center thereof. An O-ring 77 is positioned between the lower surface of the body 71 and the surface of the cavity 65 so as to surround and partially restrict the uppermost end of the passageway 62. The O-ring 77 cooperates with the notch 76 in the adjusting screw 75 to provide an adjustable opening between the passageway 62 and the passageway through the body 71 above the O-ring 77. A horizontal passageway 78 is provided between the cavity 72 and the passageway through the center of the body 71 above the O-ring 77. Thus, communication is provided between the passageway 62 and the passageway 66 with the longitudinal position of the adjusting screw 75 determining the rate of flow of fluid therebetween. A snap ring or retaining ring 79 is utilized in the cavity 65 to maintain the assembly 70 correctly positioned therein. It should be understood that other means might be utilized for adjusting the rate of flow of fluid in the passageways 62-66 but the present assembly 70 is illustrated because of its simplicity and reliability.

A passageway 85 is defined in the cap 60 having one end in communication with the compartment 61 and the other end opening external of the cap 60. The passageway 85 has a check valve generally designated 86, including a ball 87 biased 'by a spring 88, threadedly engaged in the external opening thereof to allow fluid to flow through the passageway 85 into the compartment 61 but not in the reverse direction. A conduit 89 is attached to the check valve 86 and adapted to be placed in communication with a source of fluid to be injected into the main conduit 53.

In the operation of the injector pump apparatus a flow of pressurized fluid in the main conduit 53 is controlled by some means, such as valve 90. When pressurized fluid is flowing in the main conduit 53, this fluid is free to flow into the compartment 52. Because the surface or face of the piston 20 defining a portion of the compartment 52 has a substantially larger cross-sectional area than the surface or face of the piston 20 defining a portion of the compartment 61, the total force, which is equal to pressure times area, will be greater on the lower face of the piston 20 than it is on the upper face thereof. Thus, the piston 20 will be urged upwardly in the housing 11 tending to reduce the size of the compartment 61 and increase the size of the compartment 52. A compression spring 91 is positioned generally coaxially about the piston 20 so that the upper convolution bears against the flange 16 between the housing 11 and the wall 17 and the lower convolution bears against the flange 24 at the end of the wall 23. Thus, the spring 91 provides a bias urging the piston 20 downwardly against the end cap 50. The force of the spring 91 and the difference in cross-sectional area of the upper end of the piston 20 relative to the lower end of the piston 20 should be adjusted so that the piston 21}- will move upwardly, as described, when the fluid in the main conduit 53 is at the low end of its range of pressures. Thus, whenever fluid under pressure is flowing in the main conduit 53 the piston 20 will move upwardly in the housing 11 and once the flow of pressurized fluid stops, or the pressure goes below the lowest desired value, the piston 20 will return to the position shown under the force of the spring 91.

As the piston 20 moves upwardy in the body fluid in the compartment 61 is forced outwardly through the passageways 62-66, and the condiut 67 to the main conduit 53. As previously described, the flow of fluid in the passageways 62-66 is accurately metered by the adjustable valve assembly 70 so that the fluid injected into the main conduit 53 from the conduit 67 produces the desired concentration downstream therefrom. Once the pressurized fluid in the main conduit 53 ceases to flow, the piston is urged into the position shown by the spring 91 and this reverse movement causes fluid to be drawn into the compartment 61 through the passageway 85 and check valve 86. Upon returning to the position illustrated the compartment 61 is filled with the fluid to be injected into the main conduit 53 and the entire injector pump apparatus is ready for a second cycle. One or more vents or openings 92 are provided in the housing 11 so that movement of the piston 20 does not create a pressure or a vacuum therein. Such pressure or vacuum would alter the amount of pressure required to move the piston 20 a full stroke as well as changing the proportion to make the movement non-linear, However, it should be understood that in some embodiments vents may not be utilized and such pressure or vacuum may be compensated in the pressure differential across the piston 20.

Thus, injector pump apparatus is disclosed which is completely automatic and does not require an external power source to produce the injecting action. As soon as pressurized fluid is introduced into the main conduit 53 the present apparatus is activated to inject a second fluid at a predetermined rate into the flow of pressurized fluid. Also, the apparatus is linear throughout a predetermined range of pressures for the pressurized fluid so that variations of pressure will not adversely affect the concentration of the fluid downstream of the apparatus. As fluid is forced out of compartment 61 through the passageway 62 the flow thereof causes the indicator ball 64 to move upwardly in the passageway 62 and indicia (not shown) provided on the bell-shaped cap 61 indicate the rate of flow of fluid through the passageway 62. Thus, the present apparatus provides a reliable indication of the flow rate of the fluid being injected into the main conduit 53 as well as a simple and reliable means for adjusting the flow rate.

What is claimed is:

1. Injector pump apparatus comprising:

(a) a body defining a generally cylindrical elongated chamber therein having oppositely disposed first and second ends, the cross-sectional area of said chamber adjacent said first end being smaller than the cross-sectional area adjacent said second end;

(b) a dual acting piston having first and second oppositely directed faces at opposed ends thereof mounted in said chamber for axial reciprocal movement, the cross-sectional areas and configuration of said first and second faces conforming with the crosssectional area and configuration of said chamber adjacent said first and second ends, respectively;

(c) sealing means positioned between said piston and said body for dividing said chamber into a first substantially fluid-tight compartment partially defined by said first end of said chamber and said first face of said piston and a second substantially fluid-tight compartment partially defined by said second end of said chamber and said second face of said piston;

(d) biasing means operating on said piston and normally urging said piston toward said second end of said chamber;

(e) a first passageway in said body in communication with said second compartment and adapted to be connected to a conduit having a pressurized flow of fluid therein;

(f) a second passageway in said body in communication with said first compartment and adapted to be connected to the conduit having a pressurized flow of fluid therein; and

(g) a third passageway in said body in communication with said first compartment having check valve means associated therewith for allowing the flow of fluid only into said first compartment and said third passageway being adapted to be connected to a supply of fluid to be injected into the conduit having a pressurized flow of fluid therein.

2. Injector pump apparatus as set forth in claim 1 wherein the sealing means includes a pair of rolling diaphragms affixed between said piston and said body.

3. Injector pump apparatus as set forth in claim 1 having in addition adjustable metering means aflixed to said body for controlling the flow of fluid through said second passageway.

4. Injector pump apparatus as set forth in claim 1 wherein the pressurized fluid and the fluid introduced into said first compartment through said third passageway are liquids and including flow indicating means in communication with said second passageway for indicating the flow of liquid therethrough.

5. Injector pump apparatus as set forth in claim 4 wherein at least a portion of that part of the body defining the second passageway is constructed of transparent material with said portion being oriented in a generally vertical position and including a ball constructed of material that is heavier than said liquid flowing in said second passageway and having a diameter smaller than the diameter of said passageway, said ball being positioned in said transparent portion for limited vertical movement relative to the rate of flow of liquid in the passageway through said portion.

6. Injector pump apparatus comprising:

(a) a first piston having a face thereon with a first cross-sectional area operatively mounted for reciprocating movements in a substantially fluid-tight mating cylinder;

(b) a second piston having a face thereon with a second cross-sectional area smaller than the cross-sectional area of the face of said first piston and mounted for reciprocating movements in a substantially fluid-tight mating cylinder;

(0) means attaching said second piston to said first piston for opposed reciprocating movements;

((1) biasing means operating on at least one of said pistons for urging said first piston in a direction to compress any fluid in the mating cylinder and for 8 urging said second piston in a direction to produce a partial vacuum in the mating cylinder;

(e) a first passageway in the mating cylinder of said first piston adapted to be connected to a conduit having a pressurized flow of fluid therein;

(f) a second passageway in the mating cylinder of said second piston adapted to be connected to the conduit having a pressurized flow of fluid therein; and

(g) a third passageway in the mating cylinder of said second piston having check valve means associated therewith for allowing a flow of fluid only into the mating cylinder of said second piston and said third passageway being adapted to be connected to a supply of fluid to be injected into the conduit having a pressurized flow of fluid therein.

7. Injector pump apparatus as set forth in claim 6 wherein the ratio of the cross-sectional area of the face of the first piston to the cross-sectional area of the face of the second piston is sufficiently large to produce a differential force on the first and second pistons due to a pressurized flow of fluid in the conduit larger than the force produced by the biasing means.

References Cited UNITED STATES PATENTS 2,698,710 1/1955 Pedroia 230-52 2,789,510 4/1957 Megnig 10350 3,134,304 5/1964 Hager 10350X ROBERT M. WALKER, Primary Examiner 

